1. Field of the Invention
ATM (Asynchronous Transfer Mode) networks supply connectionless data communication traffic by means of BDS (Broadband Data Service). Private local networks LAN (Local Area Networks) can be connected to the ATM network for exchanging traffic with other local networks. The present invention relates to a modification of ATM networks in order to emulate local networks so the ATM network in a simple way can manage the local network traffic, i.e. both public and private data communication services over ATM.
2. Discussion of the Background
According to previous technology one has been depending on the fact that local network traffic first is analyzed in certain nodes in the ATM network. This analysis is taking a lot of time as far as it results in an address solution, the result of which must be sent back to the customers in the local network, at which these themselves establish channels to addressees. Consequently the ATM network only functions as catalog for an address solution. A number of previous patent documents relate to this technology.
U.S. Pat. No.5,280,481 relates to a method and a device for making use of for instance MAC-protocol (Media Access Control) for communication over an ISDN network (Integrated Services Digital Network). This is effected by the ISDN network emulating a local network by converting it by means of the method and the device. The MAC addresses are managed in the interface.
EP,A1 0 473 066 describes a system for interconnection of different local networks via an ATM network. The connection is performed by means of bridges which by means of internal tables decide the destination address and by means of VCI (Virtual Channel Identifier) transmits the frame, which is divided into cells, through the ATM network.
U.S. Pat. No. 5.088.090 shows a system for the interconnection of local networks by means of bridges. The bridges, which detect whether transparent routing or source routing is to be used, perform the connection on MAC-level.
EP, Al 0 511 144 relates to a method and a device for connection of local networks to a WAN (Wide Area Network). The connection is performed by means of a so called concentration node in the local network, which node is used for making a network node interface towards the local network, and an end node towards WAN with possibility of local addressing.
The mentioned documents present different ways of connecting traffic between local networks and other networks, for instance ATM. In all cases different ways of managing the local addresses are treated.